Referring to FIG. 1, dry aluminum electrolytic capacitor most widely used among the aluminum electrolytic capacitors is so constructed that an element comprising anode aluminum foil 4 and cathode aluminum foil 5, which are wound and partitioned by separators 6, is provided in a space enclosed with an aluminum casing 1, a rubber packing 2 and a plastic plate 3. and An anode lead 7 and a cathode lead 8 are fixed to the rubber packing 2 or plastic plate 3 in holes previously bored, the separators 6 being impregnated with an electrolyte, such as a solution or organic or inorganic salt or a liquid of large ionization constant, for facilitating electrical connection of anode aluminum foil 4 with cathode aluminum foil 5. Also, the aluminum casing 1 is contracted in part to keep mechanical connection of the aluminum casing 1 and rubber packing 2.
The aluminum electrolytic capacitor constructed as described in the foregoing is often used as an electric circuit element because it is large in electrostatic capacity and low in cost. On the other hand, the circuit element has a tendency to be used in a chip because it is demanded that the productivity and the circuit element density of a substrate are expected to be improved by use of the face-bonding.
Such as aluminum electrolytic capacitor, however, contains therein a liquid, thereby creating the following problems:
1. The electrolyte is apt to vaporize due to the heat developed during the soldering process (250.degree. through 260.degree. C. at a temperature of soldering), which is remarkable especially in the dipping process of chipping the circuit element and soldering it while being dipped in molten solder, so that pressure in the aluminum casing 1 rises to break and scatter the rubber packing 2 or plastic plate 3, or the inner liquid may leak outwardly between the lead 7 or 8 and the rubber packing 2, thereby causing the characteristic of circuit element to deteriorate. Hence, it is required in designing the circuit element that the lead only comes into contact with solder, which has put a large restriction on the design.
2. The combination of several parts requires extra space in the casing, which hinders mintaturization of the element.